The invention relates to a roll crusher for crushing hot bulk material, such as, for example, cement clinker discharged from a baking kiln, having at least two crushing rolls which are arranged in parallel, are driven in opposite directions and have a rotatably mounted supporting tube, onto which in each case a multiplicity of crushing rings to be connected to the supporting tube in a rotationally fixed manner can be pushed, the outer surfaces of which crushing rings have crushing elements.
In a cement clinker production line, the blazing hot cement clinker burned from calcined raw cement meal in a rotary tubular kiln is ejected from the kiln discharge end onto a cooler, nowadays mostly onto the cooling grate of a grate cooler, is distributed on the latter and is moved by suitable conveying techniques in the longitudinal direction to the cooler discharge end, cooling air at the same time flowing essentially from bottom to top through the cooling grate and the hot bulk material layer transversely to the conveying direction. In this case, it has proved to be advantageous if the hot cement clinker, which tends to agglomerate, has as uniform a lump size as possible and uniform grain size distribution. It is therefore already known for a roll crusher having a plurality of crushing rolls arranged in parallel and rotatable in opposite directions to be arranged as an “intermediate crusher” in a grate cooler in the region of a cooling grate stage, which crushing rolls extend over the entire width of the grate cooler and have the task of comminuting in particular the large clinker lumps, which can then be cooled further after passing through the roll gaps in the adjoining grate cooler region, see, for example, brochure 7-330e of KHD Humboldt Wedag AG, dated October 1994, page 4. Clinker crushers in the form of such multiple roll crushers arranged at the clinker discharge end of a grate cooler in the material outlet shaft are also known.
In such roll crushers for crushing hot cement clinker, the roll surfaces are subjected to high mechanical and thermal stresses. EP 1 495 812 A1, for example, therefore discloses a multiple roll crusher which is arranged at the material discharge end of a cement clinker grate cooler and whose plurality of crushing rolls arranged parallel to one another and driven in opposite directions each have a rotatably mounted supporting tube construction, which constitutes a driven shaft, onto which in each case a plurality of crushing rings to be connected to the shaft in a rotationally fixed manner and having crushing elements on their outer surface can be pushed, such that, in the event of wear, the individual pushed-on crushing rings can be exchanged in a simple manner. In the known crushing rings, however, the spaced-apart crushing elements are distributed exclusively as axially parallel profiles and otherwise in their entirety in a nonuniform manner over the outer circumference of the crushing rings, as a result of which the roll gap between adjacent crushing rolls constantly narrows and then widens again during the crushing roll operation, a factor which, depending on the rotary angle position of the crushing rolls, results in nonuniform comminution of the cement clinker and a nonuniform grain size distribution of the discharge material leaving the multiple roll crusher, with the further consequence that clinker lumps that are not sufficiently broken up in the multiple roll crusher also cannot be sufficiently cooled. In addition, the varying grain band of the cement clinker has an adverse effect on the downstream grinding.